Rectifying and filtering system



Dec. 28, 1937.

Filed 001:. 24, 1935 \NVENTOR PAL/L MUELLER /g wwL/ ATTORNEY Patented Dec. 28, 1937 UNITED STATES PATENT OFFICE funken m. b. Germany Application October 24 In Germany 1 Claim.

In apparatus for A. C. which are combined with a dynamic loudspeaker, the direct current energy for the field excitation must be supplied from the battery eliminator. To this end three methods have hitherto been used:

((1) Use of a special rectifier,

(b) Parallel connection of field excitation,

(0) Field excitation in series with the remaining D. C. load. Circuit (a) is very expensive. Circuit (b) has the disadvantage that in providing the parallel connection before the filter means the excitation voltage is too high which for the sake of safety is not desirable. Parallel connection after the filter means requires a filter choke of very large dimensions. Also circuit (0) has certain disadvantages: Although the exciting winding can be used as filter choke such measure involves the disadvantage that due to the energy thereby necessary, the voltage drop produced is too large thus making it necessary to use a rectifier tube dimensioned for very high alternating voltages. Thus the net transformer and the filter condenser become expensive. It is also necessary to construct combined and non-combined apparatus in a different manner.

In accordance with the invention these drawbacks are overcome in principally using the circuit (a) yet without a special tube, instead of which in accordance with the desired condition, either a one-way or full-way rectifier is inserted by which the two systems are separately utilized. This idea will be further explained with reference to an example.

It is aimed at manufacturing a device to be sold as combined and non-combined type. In addition thereto the customer should also be ac corded the opportunity of using the non-combined device together with a special dynamic Gesellschaft fiir Drahtlose Telegraphie Berlin, Germany, a corporation of 1933, Serial No. 694,964 October 18, 1932 loudspeaker. This problem is solved in that a one way rectifier will be used with the non-combined apparatus (Figure 1). If, however, it is intended to use the apparatus as combined type or together with a special dynamic loudspeaker, instead of a one way rectifier, a two way rectifier is inserted, the two systems of which are separately used (Figure 2). The one system is further used for the amplifier. Nothing need be changed on the part connected to the net. The second system is used for exciting the dynamic loudspeaker. The supplementary means consist only of a tap at the line transformer and of a filter condenser. A further advantage resides in the simplification of construction and manufacture.

A further feature inherent to the inventive idea is the possibility of its application wherever two different voltages are supplied by a battery eliminator.

I claim:

In a power supply device for amplifiers and the like, a source of alternating current, a power transformer having a primary winding and a secondary winding, a rectifier tube provided with a cathode and two anodes, an envelope for enclosing the cathode and two anodes, a connection between the cathode of the tube and one end of the secondary winding of the transformer, a load circuit, a connection between one of the anodes of the rectifier tube and the other end of the transformer secondary said connection including the load circuit, an auxiliary load circuit and a connection between the other anode of the rectifier tube and a point of the transformer secondary intermediate the two ends thereof whereby said two loads are supplied with independently rectified different voltage current.

PAUL MULLER. 

